WEYMOUTH – A group of 21 academic economists from some of the nation’s top universities said the benefits of a proposed merger between South Shore Hospital and Partners Healthcare won’t outweigh the loss of competition.

The letter was submitted as a comment on a proposed consent decree by Attorney General Martha Coakley that would allow that merger and one between Partners and Hallmark Health System. The economists ask Suffolk Superior Court Judge Janet Sanders to reject the agreement and order a full trial in the case.

The letter was drafted by Professors Leemore Dafny and David Dranove, who are both with the Kellogg School of Management at Northwestern University outside Chicago. Both specialize in the health care industry.

In an interview, Dafny said hospital consolidations lead to higher prices and not to consumer savings.

“These are largely harmful to consumers,” said Dafny, who was deputy director for health care and antitrust at the Federal Trade Commission. “We don’t see this as an exception.”

In the letter, the economists based their opinion on a review of hundreds of hospital mergers around the country and concluded “hospital mergers have consistently failed to generate the benefits promised by their proponents.”

Dafny, who studied at Harvard and MIT, said none of the economists who signed the letter have any financial interest in the proposed merger.

“Partners’ 20-year track record of integration paired with high prices and high medical costs casts serious doubt upon its assertions that the proposed acquisitions would yield substantial efficiencies, let alone of the magnitude necessary to outweigh the alleged anticompetitive effects,” the letter stated.

Christopher Loh, a spokesman for Coakley, said the attorney general’s office worked with the federal Justice Department in investigating the case and the impact of the merger on the local health care market.

“The economists who submitted this letter unfortunately fail to recognize many of the legal factors we had to consider while making our decision,” Loh said. “We are confident that this consent judgment does more to control health costs for consumers and alter Partners’ business practices than any lawsuit would have potentially achieved. We look forward to discussing this agreement with the court.”

Loh said the attorney general’s office has received 70 comments on the proposed settlement.

One was from former Attorney General Thomas Reilly, who said the terms “impose significant restrictions on Partners which are clear, meaningful, and enforceable.”

The attorney general’s office will accept comments through Sept. 15 and will forward them to the judge in time for a Sept. 29 hearing.